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Lake Kankakee formed 14,000 years before present (YBP) in the valley of the Kankakee River. It developed from the outwash of the Michigan Lobe, Saginaw Lobe, and the Huron-Erie Lobe of the Wisconsin glaciation. These three ice sheets formed a basin across Northwestern Indiana. It was a time when the glaciers were receding, but had stopped for a thousand years in these locations.〔Dunes of Northwestern Indiana; Edward Barrett; Forty First Annual Report of Department of Geology and Natural Resources, Indiana; pg 11-22; Fort Wayne Printing Company; 1916〕 The lake drained about 13,000 YBP, until reaching the level of the Momence Ledge. The outcropping of limestone created an artificial base level, holding water throughout the upper basin, creating the Grand Kankakee Marsh. Lake Kankakee was a prehistoric lake during the Wisconsin glacial epoch of the Pleistocene Era. The lake formed during the period, when the Michigan and Saginaw lobes of the Laurentian glacier had receded back to the Valparaiso and Kalamazoo moraines. While the glacial advance became stagnant, the summer runoff formed a large lake covered parts of 13 counties in two states. Around 1840, Mr. F. H. Bradley applied the name Lake Kankakee to the lake which he thought formerly occupied the Kankakee basin.〔The Illinois Ice Lobe, Section 3, Lake Kankakee; Frank Leverett; U.S. Geological Survey, Monograph, #38; Government Printing Office; Washington, D.C.; 1899, pg 328-338〕〔Geology of Illinois, Vol. IV, 1870, pp. 226-229.〕 The sand deposits outside the marsh were the first clue that the lake existed. These sands were the result of Aeolian or wind processes, not lacustrine, or fluvial processes. He predicated that the lake would have been at an elevation of above sea level.〔The Illinois Ice Lobe; Frank Leverett; U.S. Geological Survey, Monograph, #38; Government Printing Office; Washington, D.C.; 1899, pg 328-338〕 ==Origin== The glaciers were static, only in that the glacial fronts melted at a rate matching the southward push of the ice mass. The meltwaters from the eastern edge of the Michigan Lobe and the western edge of the Saginaw Lobe ran through the Dowagiac River valley of western Michigan. Joining the ancestral St. Joseph River, reversing the flow southward towards the flat plain till plain, where South Bend, Indiana now stands. From the east, the St. Joseph River valley drained the meltwaters from the southern edge of the Saginaw Lobe and the northwestern shoulder of the Huron-Erie Lobe.〔The Glacial Lakes Around Michigan; William R. Farrand, Bulletin 4, Michigan Department of Environmental Quality, Geological Survey Division; Lansing, Michigan; revised 1988〕 The Valparaiso Moraine formed the southern flank of the Michigan Lobe as well as the northern ridge of the Kankakee Valley.〔 At the northern end of the valley, the Dowagiac River valley extended northward between the Valparaiso Moraine on the west and the Kalamazoo Moraine on the east.〔 The Kalamazoo Moraine formed one side of the melting Saginaw Lobe, with the southern flank sitting on the Sturgis Moraine. South of the Sturgis Moraine, the future St. Joseph River was a marshy plain, extending southeastward towards the toe of the Huron-Erie Lobe. First the Union City Moraine formed, then as the ice receded and again stabilized the Mississinawa Moraine formed along the front of this ice 〔 The Saginaw Lobe's meltwater flowed across the St. Joseph valley, while the Huron-Erie Lobe's meltwater and sediments first flowed into the upper Tippecanoe River.〔 When the glacier moved back to the Mississinawa Moraine, the off flowing water created the Eel River valley. The waters coming down the St. Joseph valley crossed the till plain south and east of the future South Bend entering the valley of the Kankakee River. Water from the Huron-Erie Lobe came through the upper Tippecanoe valley, spreading across the till plain, in Starke, Pulaski, Jasper, and Newton counties, merging with the shallow waters in the Kankakee basin of St. Joseph, LaPorte, Porter and Lake counties.〔 The meltwaters were trapped between the ice masses to the north and east and the Nebo-Gilboa Ridge, an offshoot of the Bloomington Moraine to the south 〔Chapter VI. The Saginaw Lobe; Frank; Monographs of the United States Geological Survey, Volume LIII, Government Printing Office, Washington; 1915〕 and the Marseilles moraine. On the west, the Marseilles moraine formed the final and lowest barrier.〔 In the vicinity of Marseilles, Illinois the waters crested the divide and created an outlet into the pre-glacial Mississippi River, creating the modern Illinois River.〔 This event is known as the Kankakee Torrent. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lake Kankakee」の詳細全文を読む スポンサード リンク
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